I became aware of the Phytochrome trigger around three years ago or more here on RIU by reading a thread from a guy that went by the handle Splifferous. He was using one of GLS's 730 nm lights on a outdoor plant. My interest was in increasing yield but the faster flower time was nice too. 730 nm is what transitions our favorite plant from one phytochrome state to the other,in easier terms from day to night. That's why outdoors flowering can start at 14 hours and indoors you use 12 hours. Without the natural 730 nm of outdoors a indoor plant takes two hours to switch states,it needs 660 nm to transition back at lights on indoors. So by using 730 at lights out indoors you eliminate the two hour transition and by doing so,you can increase your lighting schedule up to 14/10. With the extra two hours of light your plants can store more energy to grow with,thus the increased yield.
This might help understanding the advantages. Indoors at 12/12 without 730 the plant thinks it's 12/10. With 730 at 14/10 the plant thinks 14/10,our plants flowering is controlled by the length of darkness not the amount of light.